Balancing arrangement for a control body having ports

ABSTRACT

A control body in a rotor of a fluid handling device, has at least one pair of diametrically opposite high and low pressure control ports cooperating with ports in the rotor which communicate with working chambers. In order to center the control body in the rotor, only one high pressure balancing chamber is axially aligned with the low pressure control port, and only one low pressure balancing chamber is axially aligned with the high pressure control port. Only one balancing recess cooperates with each control port and is diametrically, and also in axial direction, spaced from the same whereby the control body is not bent by the pressure forces, and leakage is reduced.

United States Patent 11 1 1111 3,747,639 Eickmann July 24, 1973 [54] BALANCING ARRANGEMENT FOR A 2,328,717 9/1943 Glasner 91/492 X CONTROL BODY HAWNG PORTS FOREIGN PATENTS 0R APPLICATIONS Inventor: Karl Eickmann, 2 2 i, 934,293 H1948 France 91/492 Hayama-machi, Kanagawa-ken, 214,742 4/1924 Great Britain Japan Primary Examiner-Henry T. Kliinksiek [22] Flled' 1970 Attorney-Michael S. Striker [2]] App]. No.: 90,410

[57] ABSTRACT [30] Foreign Application Priority Data A control body in a rotor of a fluid handling device, has Nov. 24, 1969 Austria A 10964 at least one P of diametrically opposite high ahd low pressure control ports cooperating with ports in the 52 US. (:1 137/625.24, 308/9, 251/283 rotor which communicate with working chamhers- In 51 Int. Cl. Fl6k 11/06, Fl6k 39/04 Order to Center the control body in the rotor, y one [58] Field of Search 251/281, 233; high P balancing chamber is axially aligned with 7 1 5 62523, 62525, 62524; 91/484, the low pressure control port, and only one low pres- 1 486 4 303/9 sure balancing chamber is axially aligned with the high pressure control port. Only one balancing recess coop- 5 References Cited erates with each control port and is diametrically, and UNITED STATES PATENTS also in axial direction, spaced from the same whereby 3 036 528 5/1962 K] 91/ X the control body is not bent by the pressure forces, and

opp 1 3,082,696 3/1963' l-lenrichsen... 91/487 leakage ls reduced 3,187,681 6/1965 Firth et a] 91/492 X 14 Claims, 9 Drawing Figures H 17 5a 72 75 7/ 76 6 4 4Q 6 1 5 I k 5 76 i -7 a t. E 1 3 8 1 3b q F A P BALANCING ARRANGEMENT FOR A CONTROL BODY HAVING PORTS BACKGROUND OF THE INVENTION The present invention relates to the arrangement of balancing recesses for the equalization of the static pressures acting on a control body provided in the rotor of a fluid handling device, such as a compressor, pump, motor, or combustion engine.

It is known to provide fluid containing balancing recesses on cylindrical floating control bodies for balancing the pressure forces produced by the control ports in the same. Such an arrangement is, for example, disclosed in my U.S. Pat. No. 3,062,151.

In accordance with the prior art, each control port in the control body is associated with two balancing chambers located diametrically opposite the respective control port, and at opposite sides of the same as viewed in axial direction of the rotor and control body. Consequently, six leakage flows are produced for each control port, namely two leakage flows from the control port, and two leakage flows from each of the two balancing recesses. The total of these leakage flows is so great that fluid handling apparatus provided with a control body of this type, can be economically operated only up to average pressures of 150 atmospheres. At higher pressures, for example above 200 atmospheres, the leakage flow is already several percent of the total flow, and reduces the efficiency of the appara tus to an untolerable degree.

Furthermore, since the control port produces a radial pressure force opposite to two pressure forces produced by the balancing recesses at axially spaced points of the control body, the control body is bent so that the axis of the. control body is curved and does not coincide with the axis of the rotor. For pressures above 200 atmospheres, the deflection of the control body according to the prior art is over three thousandths of a millimeter so that the gap between the inner control surface of the rotor, and the outer control surface of the control body had to be increased, which causes additional leakage flows for pressures above 150 atmospheres. Fluid handlingapparatus according to the prior art cannot be economically used at pressures above 200 atmospheres, and certain uses, such as for motor car transmissions, bulldozer drives, and similar heavy equipment, are not possible.

' SUMMARY OF THE INVENTION It is one object of the present invention to overcome the disadvantages of balancing arrangements according to the prior art, and to provide a fluid handling device with a balancing arrangement by which leakage flows are substantially reduced as compared with the prior art.

Another object of the invention is to providea fluid handling device with a balancing arrangement for its control body which permits the use of the fluid han- With these objects in view, the present invention associates each control port of the control body of a fluid handling device, with a single fluid containing balancing recess by which static pressure equalization is obtained. In the preferred embodiment of the invention, the control port and the corresponding single balancing recess, are disposed in the control body diametrically opposite each other, but staggered and offset in axial direction. i

In accordance with another feature of the invention, a fluid handling device which has in its rotor a plurality of axially spaced sets of circumferentially spaced working chambers and chamber ports, is provided with a control body which has a plurality of axially spaced pairs of control ports. The pairs of control ports are circumferentially aligned with the sets of chamber ports, respectively, and the control body has a plurality of pairs of balancing recesses, the number of the pairs of balancing recesses being the same as the number of pairs of control ports, the balancing recesses of each pair being respectively aligned with the control ports of a pair of control ports, and the pairs of control ports and balancing recesses alternating in axial direction. As a result, a single balancing recess cooperates with each control port, and is spaced from the same diametrically in circumferential direction, and also in axial direction. However, the basic arrangement of the invention uses a control body having one pair of diametrically spaced control ports circumferentially aligned with chamber ports, and also having a single pair of diametrically spaced-circumferentially aligned fluid containing balancing recesses associated with the pair of control ports and being, respectively, aligned in axial directions with the control ports, so that a single balancing recess cooperates with each control port, from which it is spaced diametrically, and also in axial direction of the rotor and control body.

In the arrangement of the invention, bending forces acting on the control body are eliminated, but a tilting moment is applied by the fluid pressure forces to the control body. This tilting moment is preferably taken up by a radially acting supporting means, such as bearings, or fluid pressure chambers at the ends of the control body. These pressure chambers are provided with pressure fluid by conduits passing through the control body and being connected to the supply and discharge conduits in the same.

Preferably, fluid containing pressure ports are also provided in the stationary control surface of the control body axially aligned with portions of the control surface located between two opposite control ports.

The novel features which are considered as charac teristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a longitudinal axial section illustrating a balancing arrangement in accordance with one embodiment of the invention;

FIG. 2 is a cross section taken along line II-II in FIG.

FIG. 3 is a cross section taken along line IIIIII in FIG. 1;

FIG. 4 is a longitudinal axial sectional view illustrating another embodiment of the invention;

FIG. 5 is a cross section taken along the line VV in FIG. 4;

FIG. 6 is a cross section taken along line VI-VI in FIG. 4; and

FIGS. 7, 8 and 9 are cross sections taken along line VII-VII, line VIII-VIII, and line IXIX, respectively, in FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of FIGS. 1 and 4 differ from each other inasmuch as the embodiment of FIG. 1 is provided for use with only one set of working chambers, while the embodiment of FIG. 4 is provided for use with two axially spaced sets of working chambers. The basic features of the two embodiments are the same, and will be together described. Housing parts 71 or 81 are parts of the stator in which a rotor 4 or 14 is mounted in bearings 6 for rotation about an axis. The respective rotor 4 or 14 is provided with sets of working chambers 5 or 25, 35 which during rotation of rotor 4 or 14 first expand to receive fluid, and then contract so that fluid flows out of the same. Working chambers 5 or 25, 35 open in chamber ports 5a or 25a, 35a on inner rotor surfaces 4a or 14a. Rotors 4 or 14 have a control surface 40 or 14a sliding in sealing engagement on the stationary control surface 3a or 13a of the control body 3 or 13. In the illustrated embodiment, the control surfaces are cylindrical, and the rotor has a central bore forming the rotary control surface 4a or 14a.

The control body 3 or 13 has conduits 15, 16, 17 and 18 extending in axial direction, and, for example, conduits 15 and 16 may be high pressure conduits, and conduits 17 and 18 may be low pressure conduits. Conduits 15 to 18 connect inlet and outlet openings 78, 79 and 86, 87, 88, 89 with the control ports 1, 51 and 11, 21, 31, 41.

In a manner disclosed in other patents of the inventor, the control body 3 or 13 is mounted in a Cardan ring 74 by means of Cardan pins 75, and its fluid receiving and discharging portions 3b and 13b, located in stator 71 and 81, respectively, are provided with radially movable sealing rings 77 located in chambers 76 so that control body 3 or 13 can move to a limited extent in radial and transverse angular directions, if necessary.

In accordance with the invention, the floating control body 3 is provided with a pair of diametrically opposite fluid containing balancing recesses 2 and 52. Only one pair of balancing recesses 2 and 52, corresponding to the single pair of control ports 1 and 51 is provided. The term "single is used in the present application to denote only one. In accordance with the prior art, two pairs of balancing recesses are provided for each pair of control ports, and the pairs of balancing recesses are located on opposite sides of the pairof control ports as viewed in axial direction.

In the embodiment of FIGS. 1 to 3, the radial pressure exerted by the fluid in control port 1 on control body 3, is compensated by the radial pressure produced by the balancing recess2, and the pressure produced by control port 51 is compensated by the pressure produced by balancing recess 52. As shown in FIG. 2, the

control ports 1 and 51, respectively, communicate with conduits 15, 16 and conduits l7 and 18 in which different pressures prevail. As shown in FIG. 3, conduit 15 is connected by a conduit 92 with the balancing recess 2, and conduit 18 is connected by a conduit 91 with a balancing recess 52. Consequently, the same high pressure prevails in control port 1 and balancing chamber 2, and the same low pressure prevails in the control port 51 and balancing chamber 52, and since the pressures are diametrically opposed, no bending moment is applied to the control body 3, although a small tilting movement is produced due to the fact that each control port is displaced in axial direction from the respective associated balancing recess.

As best seen in FIG. 3, the balancing recesses 2 and 52 extend over arcs of equal circumferential length. As shown in FIG. 2, the control ports 1 and 51 extend over corresponding arcs, and are axially aligned, respectively, with the balancing recesses 52 and 2. The axial widths of the control ports and balancing chambers are also the same so that the pressure forces produced by the correlated balancing recesses and control ports, re spectively, are equal and balance each other.

Referring to the embodiment of FIGS. 4 to 9, shown in FIGS. 5 and 6, control port 11 is connected with conduit 15, control port 31 is connected with conduit 16, control port 21 is connected with conduit 18, and control port 41 is connected with conduit 17. As shown in FIGS. 9 and 8, control port 11 is connected by conduit 15 and another conduit 192 with balancing recess 12, control port 21 is connected by conduit 18 and another conduit 191 with balancing recess 22, control port 31 is connected by conduit 16, and another conduit 291 with the balancing recess 32, and control port 41 is connected by conduit 17, and another conduit 292 with balancing recess 42.

As best seen in FIG. 4, each control port is associated with only one balancing chamber which is disposed diametrically opposite, and axially staggered a small distance. High pressure balancing recess 12 cooperates with the high pressure control port 11, high pressure balancing recess 32 cooperates with control port 31, low pressure balancing recess 22 cooperates with low pressure control port 21, and low pressure balancing recess 42 cooperates with low pressure control port 41.

Consequently, the sum of the pressure forces produced by axially aligned control port 31 and balancing recess 42 is equal to the sum of forces produced by control port 41 and balancing recess 32, and the same is true for control ports 11,21 and balancing recesses 22 and 12.

Due to this arrangement, only four leakage flows through the control gap between control surfaces 3a and 4a are produced in accordance with the present invention for each set of working chambers, while in accordance with the prior art, six leakage flows are produced for each control port. For example, the control port 1 produces a leakage flow to the right and to the left, and the associated balancing recess 2 also produces a leakage flow to the right and to the left, as viewed in FIG. 1. The leakage flow conditions are the same for the other associated balancing recesses and control ports. Consequently, the two leakage flows required by the second balancing recess for each control port in accordance with the prior art, are eliminated. In this manner, volumetric losses are reduced, and efficiency of the apparatus is increased.

Since the fluid pressure forces acting on control'body 3 or 13, although radially opposed, act on axially offset points of the control body, a tilting moment acts on control body 3 or 13, which tends to angularly displace the axis of the respective control body. To sustain this tilting moment, a supporting means in the form of bear ings 7,8 in the embodiment of FIG. 1, and in the form of pressure chambers 57,56 and 58,68 in the embodiment of FIG. 4, are provided. By supporting the control body at the ends thereof against the tilting moment, the control body is centered in the rotary control surface 4a of rotor 4 and14a of rotor 14. In this manner, the control body 3 and 13 and the rotor 4 and 14 have coinciding axes, and the rotor 4 or 14 runs in a centered position about control body 3 or 13, or it may be said that the control body 4 or 14 is centered in rotor 3 or 13. An accurate centering of control body 3, 3a or 13, 13a in the control surface 4a or 14a is of particular importance because eccentric displacements of the control body increase the leakage. Due to the fact that not a bending moment, but a tilting moment is exerted on the control body, it is possible to use a divided radial bearing at 7, and a roller bearing at 8. The rollers of the A roller bearings 7 and 8 are pressed by the control body 3 or 13, which is angularly tilted, against the respective races and forced to rotate so that a flattening of the rollers by wear is prevented.

The radial width of the control gap between control body 3 or 13 and rotor 4 or 14 is exaggeratedly illustrated in the drawing, and in the actual embodiments, the radial width of the control gap is few thousandths ofa millimeter for example, 0.0001 to 0.0005 of the diameter of the control body.

As noted above, the control body 14 and the respective control ports and balancing recesses are provided for a fluidhandling device havingtwo axially spaced sets of circumferentially spaced working chambers in which two separate fluid flows may flow. One flow of pressure fluid may flow through the working chambers 25, and a separate flow of fluid may flow through the working chambers 35. It is possible that the two flows have different pressures, since each flow has separate and individual control ports and balancing recesses.

As in the embodiment of FIG. 1, a tilting moment is also exerted on control body 14 ofthe embodiment of FIG. 4. However, if the axial distance between the sets of working chambers 25, 35 and of the corresponding chamber ports 25a, 35a is sufficiently great, the areas of the control surfaces between the control ports and balancing recesses become large enough to have the effect of hydrodynamic radial bearings, so that in many cases, no additional radial bearings of the type used in the embodiment of FIG. 1, are required, particularly since the radial tilting moment for the control body 13 with a plurality of control ports and balancing recesses is smallerthan in the embodiment of FIG. 1.

However, since eccentric displacement or tilting of the control body may increase the leakage at the control body 55 times, as has been-found by tests, provided that the rotary speed of the rotor is high enough, it is advisable to provide radially effective supporting means at the ends of the control body 13. Such supporting means may be radial roller bearings, as described with reference to FIG. 1, or hydrodynamic or hydrostatic radial bearings may be used.

In the embodimentof FIG. 4, hydrostatic pressure chambers 57, 58," 67', 68 are provided which are dimensioned to compensate the radially acting tilting moment so that control body 13 floats in an exactly centered position in rotor 14. As best seen in FIG. 7, pressure chambers 57 and 58 are connected by conduits 94 with conduit 18 which communicates with control port 21, and pressure chambers 67, 68 are connected by conduits 93 with conduit 15 which communicates with control port 11.

The effective area of the hydrostatic radial bearings 57, 67, 58, and 68, and the width of the control gap in the proximity of the same, are dimensioned so that the fluid pressure in the radially effective hydrostatic bearings 57, 58, 67, 68 and in the proximity of the same, just equalizes and balances the tilting moment acting on control body 14.

The arrangements of the invention as illustrated in FIGS. 1 to 9 has an additional advantage which further increases the efficiency of the fluid handling apparatus according to the invention, particularly at high pressures. In this connection, it must be considered that in high pressure fluid handling apparatus, the fluid pressure may be several hundred kilogram per square centimeter, in which event the radial flluid pressure of a control port andthe associated balancing recess may be several tons. In the constructions of the prior art, the cylindrical control body is subjected to a central radial force in one direction, and opposite radial forces at two laterally spaced and diametrically positioned balancing recesses so that the cylindrical control body is bent at high fluid pressure to a curved condition forming an arc. Although the deflection is only a few thousandths or hundreds millimeter in the prior art arrangement, such a deflection is already intolerable for high pressure apparatus, since in such apparatus, the radial gap between the inner control surface of the rotor and the outer control surface of the control body, or the radial distance between the control surfaces, is only ten to twenty thousandths of a millimeter for diameters of the control body which are between 20 millimeters and millimeters. The small deformation of the initially straight cylindrical control body into an arc-shaped form, resulted in direct engagement of end portions of the control body with the rotor control surface, which caused over-heating and destruction of the apparatus.

The arrangement of the invention in which only one balancing recess is provided for each control port, makes the bending of the control port into arc uate shape impossible, which is due to the fact that the pressures do not act at three axially-spaced points, but at four, six or eight points so that the control body cannot be bent into an are but perhaps slightly deformed into wave shape, which produces far lower deflections.

Under practical conditions, the apparatus of the invention excludes the possibility of bending of the control body because the diameter of the same, and the axial spaces between the balancing recesses can be dimensioned so that even at very high pressures, no bending of the control body takes place. Under practical conditions, the control body 3 or 13 can be made so rigid that the radial deflection by the tilting moment is less than one-thousandth of a millimeter for several hundred atmospheres of fluid pressure. Consequently, the arrangement of the invention permits the use of very narrow control gaps, and the operation of fluid handling apparatus at the high volumetric efficiency even at very high fluid pressures.

In accordance with a further feature of the invention, additional pressure ports 9 are provided which are connected by conduits 95, 96 with the conduits l6 and 17, as shown in FIG. 7. Pressure ports 9 serve the purpose of preventing an eccentric displacement of control body 13. As shown in FIG. 6, control ports 11 and 21 extend along circumferential arcs which are separated by portions 13b and 130 of the control surface 13. Assuming that rotor 14 rotates in clockwise direction, a higher pressure prevails in the fluid film in the control gap along the portion 13b where the pressure changes between the high pressure port 11 and the low pressure port 21, than in the fluid film along the portion 130 where the pressure changes from the low pressure port 21 to a high pressure port 11. Consequently, an eccentric displacement of control body 3 or 13 takes place in the direction of the diameter connecting the portions 13b and 13c of the control surface 13a.

In accordance with the invention, the pressure ports 9 which axially aligned with the portions 13b and 130, as best seen in FIGS. 6 and 7, compensate the respective displacing pressures. One pressure port 9 is con nected by conduit 96 with the high pressure conduit 16, and the other pressure port 9 is connected by conduit 95 with the lower pressure conduit 17, assuming that the rotor 14 rotates in clockwise direction. The control surface portion 13b in which the lower average pressure prevails, is subjected to the high pressure of control port 9, and the portion 130 in which the higher average pressure prevails, is subjected to the lower pressure of the other pressure port 9 on the left of FIG. 7. The importance and the usefulness of this arrangement is the greater, the faster the rotor rotates since eccentric displacement or tilting of the control body increases the leakage flow substantially when the relative speed between rotor and control body increases. The provision of high and low pressure ports 9 between the control ports and the pressure balancing recesses, reduces the leakage losses also in arrangement of the prior art, and increases the efficiency of the same, and is consequently not limited for use with the embodiments described with reference to FIGS. 1 and 4.

The present invention has been described with reference to a cylindrical control body in a fluid handling apparatus. It is possible to apply the invention also to control bodies having planar, radially planar, conical, or spherical control surfaces, and also to obtain increase of efficiency of the respective fluid handling apparatus.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of fluid handling devices differing from the types described above. While the invention has been illustrated and described as embodied in a balancing arrangement for a control body having ports and provided in a fluid handling device, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit ofthe present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generica or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the follow claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

I claim:

1. In a fluid handling device, in combination, a balancing arrangement for a control body having ports, comprising a rotor having at least one set of circumferentially spaced working chambers for a fluid, and a rotary control surface having a set of chamber ports communicating with said working chambers for the flow of fluid into and out of said working chambers; and a control body having a stationary control surface cooperating with said rotary control surface, and having in said stationary control surface at least one pair of diametrically spaced control ports circumferentially aligned with said chamber ports, said control body having in said stationary control surface only one pair of diametrically spaced circumferentially aligned balancing recesses containing substantially stationary fluid, associated with said one pair of control ports and being respectively aligned in axial direction with said control ports of said pair so that only one balancing recess cooperates with each control port and is spaced from the same diametrically, and in axial direction, said balancing recesses and said control ports having the same pressure areas.

2. An arrangement as claimed in claim 1 wherein said chamber ports include inlet chamber ports and outlet chamber ports circumferentially aligned and diametrically spaced from each other; wherein said control body has supply and discharge conduits for a fluid connected with said control ports, respectively, so that high and low pressure control ports are located diamet-.

rically opposite each other; and wherein said balancing recesses are connected with said supply and discharge conduits so that high and low pressure balancing recesses are diametrically spaced from each other and aligned in axial direction with said low and high pressure control ports, respectively.

3. An arrangement as claimed in claim 1 wherein said rotor has a plurality of axially spaced sets of said working chambers and chamber ports; wherein said control body has in said stationary control surface a plurality of axially spaced pairs of said control ports, said pairs of control ports being circumferentially aligned with said sets of chamber ports, respectively; and wherein said control body has a plurality of pairs of said balancing recesses, the number of said pairs of balancing recesses being the same as the number of pairs of said control ports, said balancing recesses of each pair being respectively axially aligned with said control ports of a pair of said control ports, and said pairs of control ports and balancing recesses alternating in axial direction connected by conduits so that only one balancing recess cooperates with each control port and is spaced from the same diametrically and in axial direction.

4. A balancing arrangement as claimed in claim 1 wherein said rotor has a plurality of axially spaced sets of said working chambers and chamber ports; wherein said control body has in said stationary control surface a plurality of axially spaced pairs of said control ports, said pairs of control ports being circumferentially aligned with said sets of chamber ports, respectively; and wherein said control body has a plurality of pairs of said balancing recesses,the number of said pairs of balancing recesses being the same as the number of pairs of said control ports, said balancing recesses of each pair being respectively axially aligned with said control ports of a pair of said control ports and said pairs of control ports and balancing recesses alternating in axial direction connected by conduits so that only one balancing recess cooperates with each control port and is spaced from the same diametrically and in axial direction, said control body having in said stationary control surface radially effective fluid containing pressure chamber means closed by said rotary control surface and disposed axially spaced from said alternating control ports and balancing recesses at least at one end of said control body for counteracting a tilting movement of said control body due to the turning moment produced by the radial pressure exerted on said control body by the fluid in said cooperating axially spaced balancing recesses and control ports.

5. An arrangement as claimed in claim 4 wherein said pressure chamber means include a pair of diametrically spaced pressure chambers respectively axially aligned with said control ports and balancing chambers of said pairs; and wherein said control body has high and low pressure conduits respectively connected with said pressure chambers, said control ports, and said balancing chambers of said pairs.

6. Balancing arrangement as claimed in claim 4 wherein said stationary control surface is cylindrical; wherein said control portsof each pair of control ports extend over equal arcs in circumferential direction on said cylindrical control surface; wherein said stationary control surface has at least one pair of the diametrically positioned pressure chambers for compensating a tilting moment exerted by said control ports and balancing recesses on said control body, each pressure chamber extending in said circumferential direction a shorter arc than each control port.

7; Balancing arrangement as claimed in claim 4 wherein said control body has first and second axially extending high pressure ducts, and first and second axially extending low pressure ducts, said first and second high pressure ducts communicating, respectively, with one control port of each of said pairs of control ports, and said first and second low pressure ducts communcating, respectively, with the respective other control port of each pair of control ports so that fluid flows at different pressures can be maintained in said sets. of workingchambers, respectively.

8. An arrangement as claimed in claim 1, wherein said stationary control surface is cylindrical; wherein said control ports of said pair are diametrical recesses extending equal arcs in said stationary control surface so that the ends of said control ports are circumferentially spaced by portions of said stationary control surface; and wherein at least one fluid containing pressure port is provided in said stationary control surface axially aligned with at least one of said portions of said stationary control surface. s

9. In a fluid handling device, in combination, a balancing arrangement for a control body having ports for the flow of fluid into and out of said working chambers, comprising a rotor having at least one set of circumferentially spaced working chambers for a fluid, and a rotary surface having a set of chamber ports communicating with said working chambers; stationary support means; and a control body mounted on said support 'means and having a control surface cooperating with said rotary surface, and having in said control surface at least one pair of diametrically spaced control ports circumferentially aligned with said chamber ports, said control body having in said control surface only one pair of diametrically spaced circumferentially aligned fluid containing balancing recesses containing substantially stationary fluid, associated with said pair of control ports and being aligned in axial direction with said control ports of said pair, respectively, so that only one balancing recess cooperates with each control port and is spaced from the same diametrically, and in axial direction, said balancing recesses and said control ports having the same pressure areas, said control body further having in said control surface at least one pair of diametrically spaced supporting means axially aligned with said control ports and said balancing recesses, respectively, for compensating a tilting moment exerted by said controlports and said balancing recesses on said control body and tending to angularly displace said control body on said support means.

10. A balancing arrangement as claimed in claim 9 wherein said supporting means include two annular bearings disposed at the ends of said control body, respectively, surrounding the same,

11. A balancing arrangement as claimed in claim 9 wherein said supporting means include at least one pressure chamber containing fluid.

12. A balancing arrangement as claimed in claim 9 wherein said supporting means includes a pair of diametrically opposite pressure chambers containing fluid and respectively communicatingwith the two control ports of said pair of control ports and with the two balancing recesses of said pair of balancing recesses and aligned with thesame in axial direction.

13. In a fluid handling device, in combinatioma balancing arrangement for a control body having ports, comprising a rotor having at least one set of circumferentially spaced working chambers: for a fluid, and a rotary surface having a set of chamber ports communicating with said working chambers; stationary support means; and a control body mounted on said support means and having a control surface cooperating with said rotary surface, and having in said control surface at least one pair of diametrically spaced control ports circumferentially aligned with said chamber ports, said control body having in said control surface only one pair of diametrically spaced circumferentially aligned balancing recesses associated with said pair of control ports and being aligned in axial direction with said control ports of said pair, respectively, so that only one balancing recess cooperates with each control port and is spaced from the same diametrically, and in axial direction, said balancing recesses and said control ports having the same pressure areas, said control body further having in said control surface at least one pair of diametrically spaced pressure chambers axially aligned with said control ports and said balancing recesses, re-' spectively, and having smaller pressure areas than said control ports and balancing recesses for compensating a tilting moment exerted by said control ports and said balancing recesses on said control body and tending to i angularly displace said control body on said support means.

14. Balancing arrangement as claimed in claim 13 wherein said control surface is cylindrical; wherein said control ports of said pair of control ports and said balancing recesses of said single pair of balancing recesses extend over equal arcs in circumferential direction; and

wherein said pressure chambers extend in circumferential direction over shorter arcs than and balancing chambers.

t K I I said control ports 

1. In a fluid handling device, in combination, a balancing arrangement for a control body having ports, comprising a rotor having at least one set of circumferentially spaced working chambers for a fluid, and a rotary control surface having a set of chamber ports communicating with said working chambers for the flow of fluid into and out of said working chambers; and a control body having a stationary control surface cooperating with said rotary control surface, and having in said stationary control surface at least one pair of diametrically spaced control ports circumferentially aligned with said chamber ports, said control body having in said stationary control surface only one pair of diametrically spaced circumferentially aligned balancing recesses containing substantially stationary fluid, associated with said one pair of control ports and being respectively aligned in axial direction with said control ports of said pair so that only one balancing recess cooperates with each control port and is spaced from the same diametrically, and in axial direction, said balancing recesses and said control ports having the same pressure areas.
 2. An arrangement as claimed in claim 1 wherein said chamber ports include inlet chamber ports and outlet chamber ports circumferentially aligned and diametrically spaced from each other; wherein said control body has supply and discharge conduits for a fluid connected with said control ports, respectively, so that high and low pressure control ports are located diametrically opposite each other; and wherein said balancing recesses are connected with said supply and discharge conduits so that high and low pressure balancing recesses are diametrically spaced from each other and aligned in axial direction with said low and high pressure control ports, respectively.
 3. An arrangement as claimed in claim 1 wherein said rotor has a plurality of axially spaced sets of said working chambers and chamber ports; wherein said control body has in said stationary control surface a plurality of axially spaced pairs of said control ports, said pairs of control ports being circumferentially aligned with said sets of chamber ports, respectively; and wherein said control body has a plurality of pairs of said balAncing recesses, the number of said pairs of balancing recesses being the same as the number of pairs of said control ports, said balancing recesses of each pair being respectively axially aligned with said control ports of a pair of said control ports, and said pairs of control ports and balancing recesses alternating in axial direction connected by conduits so that only one balancing recess cooperates with each control port and is spaced from the same diametrically and in axial direction.
 4. A balancing arrangement as claimed in claim 1 wherein said rotor has a plurality of axially spaced sets of said working chambers and chamber ports; wherein said control body has in said stationary control surface a plurality of axially spaced pairs of said control ports, said pairs of control ports being circumferentially aligned with said sets of chamber ports, respectively; and wherein said control body has a plurality of pairs of said balancing recesses, the number of said pairs of balancing recesses being the same as the number of pairs of said control ports, said balancing recesses of each pair being respectively axially aligned with said control ports of a pair of said control ports and said pairs of control ports and balancing recesses alternating in axial direction connected by conduits so that only one balancing recess cooperates with each control port and is spaced from the same diametrically and in axial direction, said control body having in said stationary control surface radially effective fluid containing pressure chamber means closed by said rotary control surface and disposed axially spaced from said alternating control ports and balancing recesses at least at one end of said control body for counteracting a tilting movement of said control body due to the turning moment produced by the radial pressure exerted on said control body by the fluid in said cooperating axially spaced balancing recesses and control ports.
 5. An arrangement as claimed in claim 4 wherein said pressure chamber means include a pair of diametrically spaced pressure chambers respectively axially aligned with said control ports and balancing chambers of said pairs; and wherein said control body has high and low pressure conduits respectively connected with said pressure chambers, said control ports, and said balancing chambers of said pairs.
 6. Balancing arrangement as claimed in claim 4 wherein said stationary control surface is cylindrical; wherein said control ports of each pair of control ports extend over equal arcs in circumferential direction on said cylindrical control surface; wherein said stationary control surface has at least one pair of the diametrically positioned pressure chambers for compensating a tilting moment exerted by said control ports and balancing recesses on said control body, each pressure chamber extending in said circumferential direction a shorter arc than each control port.
 7. Balancing arrangement as claimed in claim 4 wherein said control body has first and second axially extending high pressure ducts, and first and second axially extending low pressure ducts, said first and second high pressure ducts communicating, respectively, with one control port of each of said pairs of control ports, and said first and second low pressure ducts communcating, respectively, with the respective other control port of each pair of control ports so that fluid flows at different pressures can be maintained in said sets of working chambers, respectively.
 8. An arrangement as claimed in claim 1, wherein said stationary control surface is cylindrical; wherein said control ports of said pair are diametrical recesses extending equal arcs in said stationary control surface so that the ends of said control ports are circumferentially spaced by portions of said stationary control surface; and wherein at least one fluid containing pressure port is provided in said stationary control surface axially aligned with at least one of said portions of said stationary control surface.
 9. In a fluid handling device, in combination, a balancing arrangement for a control body having ports for the flow of fluid into and out of said working chambers, comprising a rotor having at least one set of circumferentially spaced working chambers for a fluid, and a rotary surface having a set of chamber ports communicating with said working chambers; stationary support means; and a control body mounted on said support means and having a control surface cooperating with said rotary surface, and having in said control surface at least one pair of diametrically spaced control ports circumferentially aligned with said chamber ports, said control body having in said control surface only one pair of diametrically spaced circumferentially aligned fluid containing balancing recesses containing substantially stationary fluid, associated with said pair of control ports and being aligned in axial direction with said control ports of said pair, respectively, so that only one balancing recess cooperates with each control port and is spaced from the same diametrically, and in axial direction, said balancing recesses and said control ports having the same pressure areas, said control body further having in said control surface at least one pair of diametrically spaced supporting means axially aligned with said control ports and said balancing recesses, respectively, for compensating a tilting moment exerted by said control ports and said balancing recesses on said control body and tending to angularly displace said control body on said support means.
 10. A balancing arrangement as claimed in claim 9 wherein said supporting means include two annular bearings disposed at the ends of said control body, respectively, surrounding the same.
 11. A balancing arrangement as claimed in claim 9 wherein said supporting means include at least one pressure chamber containing fluid.
 12. A balancing arrangement as claimed in claim 9 wherein said supporting means includes a pair of diametrically opposite pressure chambers containing fluid and respectively communicating with the two control ports of said pair of control ports and with the two balancing recesses of said pair of balancing recesses and aligned with the same in axial direction.
 13. In a fluid handling device, in combination, a balancing arrangement for a control body having ports, comprising a rotor having at least one set of circumferentially spaced working chambers for a fluid, and a rotary surface having a set of chamber ports communicating with said working chambers; stationary support means; and a control body mounted on said support means and having a control surface cooperating with said rotary surface, and having in said control surface at least one pair of diametrically spaced control ports circumferentially aligned with said chamber ports, said control body having in said control surface only one pair of diametrically spaced circumferentially aligned balancing recesses associated with said pair of control ports and being aligned in axial direction with said control ports of said pair, respectively, so that only one balancing recess cooperates with each control port and is spaced from the same diametrically, and in axial direction, said balancing recesses and said control ports having the same pressure areas, said control body further having in said control surface at least one pair of diametrically spaced pressure chambers axially aligned with said control ports and said balancing recesses, respectively, and having smaller pressure areas than said control ports and balancing recesses for compensating a tilting moment exerted by said control ports and said balancing recesses on said control body and tending to angularly displace said control body on said support means.
 14. Balancing arrangement as claimed in claim 13 wherein said control surface is cylindrical; wherein said control ports of said pair of control ports and said balancing recesses of said single pair of balancing recesses extend over equal arcs in circumferential Direction; and wherein said pressure chambers extend in circumferential direction over shorter arcs than said control ports and balancing chambers. 